Currently, known developing cartridges are divided into two types, that is, an integral cartridge and a divided cartridge. The divided cartridge needs to be matched with a drum assembly and then is installed into a laser printer together with the drum assembly, and then it can be normally used. This type of developing cartridge (that is, the divided cartridge) generally includes at least: a cartridge body, a supply roller, a doctor blade, a developing roller and a memory unit. The developing cartridge realizes data communication by direct contact between a terminal of the memory unit and a terminal contact point on the laser printer.
FIG. 1-FIG. 4 show a structure of a developing cartridge used in the prior art. Reference may be made to FIG. 1-FIG. 4, a developing cartridge 100 (100K, 100C, 100M, 100Y) is detachably installed into the main body 10 of a laser printer 1 along an installation direction A, where the developing cartridge 100 includes a cartridge body 110, a power reception unit 170 is provided on the end of one side of the cartridge body 110 close to a developing roller 140, a driving force reception unit 160 is provided on the end of the other side of the cartridge body 110 close to the developing roller 140, and a memory unit 180 is then provided on a back surface 101 of the cartridge body 110 of the developing cartridge 100 along the installation direction A of the developing cartridge 100, the memory unit is closer to the power reception unit 170 in relative to the driving force reception unit 160 and the memory unit 180 is provided with four terminals 181.
With reference FIG. 3, the terminal contact point 13 on a cover 11 of the laser printer includes an end surface 131 and a side surface 132.
When the developing cartridge 100 is installed into the main body 10 of the laser printer 1 and the cover 11 is closed, the terminals 181 of the memory unit 180 come into contact with the front end surfaces 131 of the terminal contact points 13 on the cover 11. As shown in FIG. 3, a circuit board 111 is provided inside the cover 11, and the electrical connections between the terminal contact points 13 on the cover 11 and the circuit board 111 are achieved via a spring 14. A press member 12 is provided on the cover 11 and is juxtaposed with the terminal contact point 13 at a certain distance, and when the cover 11 is closed, the press member 12 imposes a forward push force on the developing cartridge 100 installed in the main body 10, which may restrict the developing cartridge 100 from shifting forward and backward.
When the laser printer 1 starts to work, electrical contact parts 171 of the power reception unit 170 of the developing cartridge 100 are connected to the main body 10 to perform electrical conduction, a connecting gear 161 of the driving force reception unit 160 of the developing cartridge 100 is engaged with a power transmission gear 81 on the main body 10 to bring a driving force, then the connecting gear 161 is engaged with a developing roller gear 162 to perform power transmission, and the terminals 181on the back surface 101 of the developing cartridge 100 come into contact with the end surfaces 131 of the terminal contact points on the cover 11 to perform data communication.
Based on the prior art as described above, we know that the memory unit generally has two sides, where the front side is disposed with terminals that come into contact with the terminal contact points on the cover of the laser printer directly, and the reverse side is disposed with a memory as well as a capacitor, a resistor or other electronic components that are connected to the memory. When the terminals on the front side of the memory unit come into contact with the terminal contact points on the cover directly, the terminal contact points on the cover squeeze the memory to some degree to enable those electronic components welded onto the reverse side of the memory unit to become deformed or displaced due to the squeeze, thus the memory unit cannot work normally or even gets damaged, thereby affecting the developing cartridge to perform communications with the laser printer via the memory unit.
When a plurality of developing cartridges is installed into the main body of the laser printer together, there will be a certain gap between the developing cartridges. Moreover, the developing cartridges usually enter and exit from the main body of the laser printer by the cooperation of a pair of or pairs of guide rail protrusions on two side plates of the developing cartridges with guide rails at two corresponding inner sides of the main body of the laser printer, and in order to easily install the developing cartridges into the printer and easily remove them from the printer, the guide rail protrusions on the developing cartridges must be in clearance fit with the guide rails inside the main body of the laser printer, in this case, when the laser printer starts to work, a driving force will cause the developing cartridges to vibrate up and down between guide clearances, this will bring about effects in two aspects: in one aspect, due to small contact areas between the terminals of the memory unit on back surfaces of the developing cartridges and the end surfaces of the terminal contact points on the cover, when the developing cartridges are vibrating up and down, elastic elongating and shortening of the end surfaces of the terminal contact points are only in front and back directions, and has no limitation on the upward and downward vibrations of the developing cartridges, this will cause up and down misplacements between the terminals of the memory unit and the terminal contact points on the cover, leading to unstable contact, and finally affecting communications between the developing cartridges and the laser printer; in the other aspect, since the developing rollers and photo-sensitive drums perform regular rotations under a driving force, vibration of the developing cartridges will increase unnecessary shifting between the developing rollers and the photo-sensitive drums, this will be bound to affect the developing process, and finally affect printing quality.
For this reason, people hopes to have a developing cartridge, which not only is capable of providing good contacts and stable communications between terminals of the memory unit of the developing cartridge and terminal contact points on a cover, but also is capable of decreasing vibrations of the developing cartridge during a printing process, avoiding to affect the developing process and guaranteeing good printing quality.